Requires

Carth the Lion must be on the battlefield. Karn, the Great Creator must be on the battlefield. Ugin's Nexus must be on the battlefield. Oath of Teferi must be on the battlefield. Krark-Clan Ironworks must be on the battlefield. Mana needed: each extra turn

Steps

1. Activate Krark-Clan Ironworks by exiling Ugin's Nexus, adding .
2. Ugin's Nexus triggers, causing you to take an extra turn after this one.
3. Activate Karn's first loyalty ability by putting two loyalty counters on it, causing any artifact to become an artifact creature until end of turn.
4. Activate Karn's second loyalty ability by removing a loyalty counter from it, returning Ugin's Nexus from exile to your hand.
5. Move to your next turn.
6. Cast Ugin's Nexus by paying .
7. Repeat.

Results